High-speed, high-resolution 1-µm OFDI was applied in vivoto the human eye of a healthy volunteer. Data acquisition wasdone at a speed of 100,000 axial scans/s over a depth rangeof 2.7 mm with an axial resolution of 5.0 µm in tissue.B-scans were acquired with 1500 axial scans over a lateral distanceof 1.42 mm to obtain sufficient correlation of the speckle noisein subsequent axial scans. The Doppler phase accuracy of thesystem is measured to be 0.4 degrees as evaluated on a mirror.Phase difference maps were obtained to visualize the bi-directionalblood flow in the choroid and retina.

Results:

Bi-directional blood flow was observed in both the choroidaland retinal regions. The imaging can pick up blood flow on bloodvessels that are as small as 35 µm in diameter and asdeep as the lower part of the choroid. Particularly in the choroidalregion, blood flow can be detected in areas where the intensityimage does not reveal the presence of blood vessel structures(see Figure 1).

Conclusions:

Doppler images from high-speed, high-resolution 1 µm OFDImeasurements can be used to reveal bi-directional blood flowin the human choroid. Because it reveals additional informationapart from the intensity images, it has the potential for bettervisualization and therefore better evaluation of the blood perfusionin the choroid.